If you're looking to enhance your outdoor plant box with potassium-accumulating plants, you're on the right track. Potassium is essential for plant health, aiding in water regulation, disease resistance, and overall growth. Here are some of the best plants to consider for your garden:

1. Comfrey (Symphytum officinale) – A powerhouse for potassium, comfrey’s deep roots draw nutrients from the soil, making it an excellent natural fertilizer.

2. Banana Plants (Musa spp.) – Known for their high potassium needs, banana plants thrive in outdoor boxes and enrich the soil as they grow.

3. Nasturtiums (Tropaeolum majus) – These vibrant flowers accumulate potassium while also repelling pests, making them a dual-purpose choice.

4. Sunflowers (Helianthus annuus) – Sunflowers absorb potassium efficiently and add a striking visual appeal to any garden.

5. Sweet Potatoes (Ipomoea batatas) – Both the foliage and tubers benefit from potassium, making sweet potatoes a practical and nutritious addition.

By incorporating these plants into your outdoor plant box, you’ll create a nutrient-rich environment that supports lush, healthy growth. Happy gardening!